Prostaglandins F in uterine venous plasma, ovarian arterial and venous plasma and in ovarian and luteal tissue of pregnant and nonpregnant ewes.

Ovarian venous, ovarian arterial and uterine venous blood were collected from the same side as a corpus luteum in 10 nonpregnant and 10 pregnant ewes at day 15 postestrus. Both ovarian and uterine venous samples were collected by venipuncture. Ovarian arterial blood was collected into heparinized centrifuge tubes after a small portion of the artery was dissected free from mesovarium and then severed. Arterial blood flow was estimated by timed collection. Ovaries and corpora lutea were removed, frozen in .vials placed in liquid nitrogen, weighed and stored at 2 0 C. Prostaglandins F (PGF) in plasma and tissue were quantified by use of radioimmunoassay. Nonpregnant. and pregnant ewes did not differ in concentration (ng/ml) of PGF in plasma from uterine veins (7.1 + 3.4 and 5.2 + .9), ovarian arteries (.6 + .3 and 1.1 -+ .3) or ovarian veins (.6 + .1 and .8 -+ .3). The rate of blood flow from the severed ovarian artery was higher (P<.05) in the pregnant ewes (4.2 -+ 1.6 vs .9 + .2 ml/min). The quantity of PGF apparently being transported to the ovary in arterial plasma was higher (P<.05) in pregnant (2.1 -+ .5 ng/ml) than in nonpregnant ewes (.5 + .2 ng/min).